Carol Hunter, the executive editor of the newspaper — The Des Moines Register — said Mr. King’s son Jeff King denied a request for credentials to the event, calling the newspaper in an email a “leftist propaganda media outlet with no concern for reporting the truth.”

Mr. King narrowly defeated his Democratic opponent, J. D. Scholten, earning a ninth term in Congress, according to The Associated Press. Jeff King is a paid staff member on his father’s campaign.

Ms. Hunter called the move “disappointing,” noting that by shutting out The Register from his event, Mr. King was also shutting out his constituents from access to his comments.

“Our coverage of Representative King, in this race, and his work in Congress, has been fair and objective,” she said. “His campaign hasn’t contacted us in recent months to claim otherwise.”

Still, she said other news media outlets offered Tuesday to provide video of Mr. King’s remarks to The Register.

“We will do everything possible to still provide comprehensive coverage for our readers in Iowa and across the country,” Ms. Hunter said.

Mr. King’s campaign did not immediately respond to a request for comment on Tuesday night. Ms. Hunter said her reporters had not received any additional comment or correspondence from the campaign after getting the terse email response earlier Tuesday.

After 8 p.m. Tuesday, other reporters seeking to cover Mr. King’s party began posting messages on Twitter saying that they too had been denied access.

Tony Leys, a reporter at The Register, wrote that along with himself, a reporter from The Storm Lake Times and an editor at The Weekly Standard had been “shooed” away from Mr. King’s event. And Christopher Mathias, a national reporter at HuffPost, tweeted that he had been “kicked out” of Mr. King’s party by Jeff King.

“When I asked why, he said to refer to a statement given to @DMRegister, also banned from tonight’s party,” Mr. Mathias said.

The congressman has a history of making remarks seen as racist. But some of his recent tweets and other comments — including an endorsement for a Toronto mayoral candidate who had previously recited the 14-word manifesto used by neo-Nazis — have drawn especially critical rebukes. At least three large agriculture businesses have announced they will no longer support Mr. King because of his conduct.

On Monday, The Weekly Standard reported that at a campaign event, Mr. King said he hoped Justices Elena Kagan and Sonia Sotomayor “will elope to Cuba.”